The document discusses the grain size measurements of cuttings samples from an oil-bearing sandstone reservoir, using a pencil lead as a scale reference (0.5mm wide). It highlights various grain sizes, with lower very fine grains equating to coarsest silt, while identifying differences between oil-stained and cemented samples. Images depict the samples' color variations and textures under ultraviolet and white light, emphasizing the quality of the reservoir based on grain characteristics and staining.